Previous research suggests that low birthweight (LBW) and perinatal complications associated with it may constitute risk factors for neurologic and psychiatric disorders in children and adults. The hypothesis requires further investigation to specify the risk and identify early signs for disorders. This proposal is for a follow-up study of a cohort of 285 children with birthweights <2000 gram, born in 1983-1985 in a major hospital in Detroit, Michigan. Two comparison groups will be selected from the cohort of normal birthweight children born in the same hospital in that period: (1) a randomly select sample of 450 children with no history of perinatal complications, and (2) all 195 children with a history of perinatal complications. Extensive perinatal data are available from medical records, including information on medical complications in the neonatal period. Using a protocol for locating subjects developed in previous research, we will contact families and collect data in 1989-1992, as each birth-year cohort reaches 6 years of age. Neuropsychologic tests, with demonstrated prognostic utility for later functioning, will be administered to the children. Information will be obtained from mothers and teachers on child psychopathology and social functioning and from mothers on family environment, mothers' IQ, mothers' psychiatric disorder and history of psychiatric disorder in other first degree relatives. We will examine the extent to which: 1) LBW increases the risk for neuropsychologic and behavioral problems at 6 years of age; 2) Perinatal complications increase the risk for these sequelae; 3) A family history of psychiatric disorder, social class and factors in the family environment affect the relationship of LBW and perinatal disease to these sequelae. Data from this study will be used for planning a future follow-up study, when Specific Developmental Disorders (Learning Disabilities) and DSM III Axis I childhood onset disorders will be diagnosed. The identification of neuropsychologic and behavioral antecedents of later disorders could lead to early intervention to prevent psychiatric sequelae and school failure in LBW children.